Delayed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibia after pin tract infection: two case reports

BACKGROUND Pin tract infection is a common complication of external fixation. It usually heals after treatment with debridement, antibiotics, and/or pin removal, only rarely developing into delayed osteomyelitis. We treated two patients with delayed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibia following pin tract infection. CASE PRESENTATION One patient, a diabetic 60-year-old Japanese man, underwent definitive external fixation using an Ilizarov fixator for postoperative osteomyelitis of an open fracture of his left ankle. One year after removing the external fixator, he developed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibial pin site. He underwent surgical debridement four times. No recurrence was seen 2 years 8 months after the last debridement. Another patient, a healthy 38-year-old Japanese man, underwent bilateral temporary external fixation for a right ankle open fracture and a comminuted fracture of the left tibial plateau. Three months after removal of the external fixator, he was diagnosed with methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the bilateral tibial pin sites. He underwent surgical debridement three times, but the infection of his right tibia persisted. Finally, a gastrocnemius muscle flap was placed. No recurrence was seen 2 years after this last surgery. CONCLUSIONS Pin tract infection should not be considered a minor complication because osteomyelitis may develop, requiring treatment that is more aggressive than curettage of the pin tract. A gastrocnemius flap is a useful treatment option for refractory osteomyelitis because flap harvest causes less functional disturbance and is a relatively easy surgical technique.